Statistical Process Control (SPC) is a powerful tool to analyze the stability of processes by using control charts to compare the measurable attributes of the process output against the natural limits of process variation. If the observed variability of the attributes is within the range of variability from natural causes, the process is said to be under statistical control. Depending on the nature of the process and the type of attributes to be analyzed, there exist different control chart types which correspond to different natural causes of variation.
Using Statistical Process Control techniques to analyze and control the performance of process steps in production processes is established and approved for decades. For some years there exist approaches to apply Statistical Process Control (SPC) also for analyzing the performance of software development processes to manage software development efforts and to effect software process improvement.